Tractor-engine.



C, CoLAHAN. TRACTOR ENGINE.

APPLICATION HLED 0CT.4. i917. 12297104. Patented Mar. 11,1919.

Z SHEETS-SHEET L C. COLAHMIl TRACTOR ENGINE.

APPLICATION FILED ocT.4. I9I7.

Patented Mr. 11,1919.

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UNITED STATES PATENT oEEIoE;

cnsnnss coLAHAN, or srocarngpv, caLIronNIA.

Timo.Tonfirronrru To all 'whom it may concern:

Be it known that I, CHARLES comun?, a citizen of the United States, residing at Stockton, in the county of San Joaquin and Stateof California, have invented certain new and useful Improvements4 in Tractor- Engines; and I do hereby declare the following to be a full, clear, and exact descri tion of the invention, such as will enabe others skilled in the art to which it appertains to make and use the same. My invention relates to improvements in tractor engines or vehicles, and relates particularly to tractor engines of the so-called caterpillar type in which the power of the engine is transmitted to an endless apron or be t, uponl the ground,"t,his belt being sup6 ported nby a series of spools, rollers or truck wheels lso'thatthe tractive `effort .or pull of the engineis distributed over a compara. tively lon extent, thereby securing better grip on t e surface of the ground, at the same time avoidin the vexatlon and trouble caused by the sin ting 'and slipping of the wheels when wheels are used. Engines of this type are sometimes said to ein loy a selflaying traction member. `'My mvention relates particularly to improvements in such member, and I provide a device in whehlsuch members are free to yield verticall in their travel, and conform-substantial y toV the, contour of the ground over which they pass, maintaining a uniform traction power and utilizin the traction members more perfectly thanghas heretofore been done in machines of this class.

All parts coperate in these vertical movements, utilizing the traction members, and

securing the desired flexibility, which is iin-y portant to machines of this class. v

My invention relates to mechanisnnof this character, having two independent parallel self-laying tracks, one on each side or the machine, and my invention relates especially to the manner of construction and o eration of these tlexible, vertical side carrying and supportin frames that oarr the runchain tread of t e tractor.

ning ar an l l itiethe abm'e and other objects in view,

my invention has particular 'relation to the Specicaton of Letters Patent.

,y of construction.

- I employ ati-ack apron 1` provided `with shoes 2 of usual pe with lugs or users 3, -if desired. Tie apron-s cari-rd0 over drive sprockets 5 usually free from the ground, and I. provide between saidrsprockets, on eachY side or wherever an apron is used, truck rollers 6. Said rollers carry the load and transmit it tothe track or apron. There are six of these rollers in my construction, between each air `of sprocket wheels, and these six 1 ers are 1n two groups ried in pivoted frames 10.

These .frames are 'pivotally secured on` axles 7 rejecting horizontally from the side of tie main frame 11' of the tracto andere each provided with arms 8, eac

extending transversely across the pivotal point or supporting axl'e back over and parallel substantially to-the truck-carrying part of the other frame. Each arm is vleldmgly supported on springs 9 located on the ltop of its opposite or com anioh frame, thus y 'forming a perfectly exi le X-shaped suport, with an equally cooperating yielding onction that more evenly distributes the load and thus obviates the friction or dead load prevalent aty this point inotherforms One of the frames is forked as seen in Fig'. 3, and at th'e pivot point straddles the other. Any' pressure on one frame is transmitted. through the springs directly t0 its companion frame. I

provide a replaceable section 12. whereby the frames may be brought together.

It will be noted that I have devised flexi- Patentea Mar. 11, 1919; nppuuatmmeeoctaber 4, 1an. serial no. 194,788.

of three each, as shown, and are carble yielding supports for my rollers whereby any desired amount of flexibility is secured and the belt or apron, or track as it is sometimes called, may conform readily to Vthel shapeorrcontoiir of the ground and at the same time the springs 9 enable each group of rollers to yield to any inequality or obstruction under the track, at the sameY time yieldingly transmitting its lift due to such obstruction to the rollers on its mating or correlated frame. The two frames constitute in etect one Vsupport tilting about' the fra-nies not only tilt but yield and in Veach case each frame 10 transmits to 'its corresponding companion frame the pres-V sure diie to yielding, so that each takes up part of the load when the other is subjected to excessive load or ressure.` The frames are of ,the same size y` preference and by preference they have the samenumber of rollers and extent of bearing surface whereby uniformity of actionA is secured. The reverse is the case too, so that if either frame tends to sink into -a depression, the conipanion frame and its rollers simplfy get a ittle more load and compensate or any variation, thus tending to keep the device on an even keel. 'In fact, since there are two o'f said aprons or tractor belts, one on each side and two frames to each belt, the four frames behave 4st )niewhat like the legs and feet of 4'an animal Walking oveip rough ground. If one foot rests u on, say, a hummock, it yields Va little and t e 1weight is distributed to the other foot on the same side (or end) and in yfact'- to the other three feet i and the animal, especially if it be one like, say a deer, whosemotions are well ordinated, mov'es evenly along without trouble or annoyance. In a sense my springsbe#y have like the muscles and `joints of such an animal and myframe, ina way, like its limbs. The joint abouttlie axle 7is, in av sense, a knee joint vand the movement controlled by the spring somewhatlike a hip joint.

I provide adjustable thrust rods,` 10' for keeping the track at proper tension.l My

rollers are each mounted u on a suitable axis 11 in its pivotedframe. is bqrne by the sprockets. It will be noted that Iv have devised a compensating support for the trucks or framesof a tractor .engine whereby flexibility and ease of yield are important to the traction members ot: a truck, and ability to conform to inequahties of surface without niuch'jar or strain. Jerking of the, frames over an obstruction -is largely controlled andA eliminated too by the stretched traction belt.

.What I claim as new and desire to secure hv Letters Patent. of the, United-.States is 1. In a traction engine, inr combination, a` traction belt, s rockets over which said belt is carried and by which it is driven, rollers,

a pair of frames on which said rollers are mounted, a common pivot for said frames,

`and sprinfs between said frames, whereby when one rame yields to an obstruction, the

effectis transmitted to and compensated forby the companion frame and the rollers thereon.

2. In a tractionengine, in combination, a tractionbelt, sprockets over which said belt is carried and by which it is driven, rollers,

a pairof frames on which said rollers are mounted, a common pivot for said frames, an extension on each of said frames and a spring between each of said extensions and the other frame, whereby when one frame yields to.an obstruction, the effect is trans- `mitted to and com ensated for by the coinpanion frame and t e rollers thereon.

3. In a traction engine, in combination, a traction belt, sprockets over which said belt is carried and by which it is driven,'rollers between said sprockets, said rollers being divided into groups of even number, frames of equal size in which said rollers are mounted, one group for each frame, a pivot on which said frames are mounted, and yielding connections between said frames, whereby when one frame yields to an obstruction the companion frame takes up part of the loss in compensation.

4. In a traction engine, in combination, a traction belt, s rockets over which said belt is carried and y which it is driven, rollers, a pair of frames on which said rollers are mounted, a common pivot for said frames, an arm on each of said frames extending back over and parallel to the roller carrying part ofthe other` frame, and a yielding l connection between each frame and e roller carrying part of the other frame, whereby by/ the companion frame and ithe rollers thereon.

5. In a traction engine,in combination, a

l traction belt, sprockets over which said belt is carried, .frames within said belt, ashaft ,l on the main frame, on which said frames one of the weight 4are pivoted, an extension arm on each of said frames, yieldiri means between each said arm and the oier frame, and truck wheels in each said frame.

6. In a traction engine, in combination, a traction belt, wheels lfor driving said belt, a flexible X-shaped support within said belt weight supporting means on the members o ,said flexible X-shaped support, and means whereby said members are kept apart or distended.

7 Ina tractor, in combination, a traction belt, means for carrying and driving said belt, a flexible X-sha ed support of two members within said be t, an axle projecting from the main frame on which said support? is pivobed, and springs between. said memstruction the e'ect of *its-.lift is transmitted bers on either side of said axle. to the other frame.

8. In a tractor, in combination, a traction In testimony whereof I affix my signabelt, means for enrryin and drivin said ture. 6 belt, rollers within said elt, pivoted rames 1 t HAS. COLAHAN.

carrying said rollers, and yielding connec- Witnesses tions directly between said frames, whereby M. H. COLAHAN,

when one frame is made to pass over n ob- L. HUGHES. 

